Electrochemical product



United States Patent O This application is a division of our application Serial No. 36,750 filed June 17, 1960, now Patent 3,141,836.

The present invention is directed to improved baths and 3,232,718 iatented-Feb. 1, 1%66 lustrous. We have been able to increase brightness to (i) hazy-bright, a slight background, haze in an essential- 1y clear deposit, and (ii) clear-bright, brightness approaching that normally associated with a mirror. By using the various additives specified hereinafter, it is possible to obtain hazy-bright and/ or clear-bright deposits. These deposits are lustrous. Lustrous and bright deposits are obtained from acid baths containing, as a brightener, phenylpropiolic acid; phenylpropiolic amide; triaminotriphenyl methane; l-(p-aminophenyl)-3-methylpyrazole; stearamidopropyldimethyl (fl-hydroxyethyhammonium dihydrogen phosphate; or l,5-diphenylcarbohydrazide.

These brightdeposits are physically different from any heretofore produced. They apparently have a fingerprocess for electroplating tin-nickel alloys and to bright g a n Strucillfey differ pp y in the grain tin-nickel electrodeposits. orientation with strong layering in the 300 plane. X-ray Plating baths for electrodepositing tin-nickel have exdiffraction data follows:

TABLE I Published X-ray data. Observed intensity d/n (Plane) ANo bright- BNo bright- C-Brightener D-Brightener h It 1 ener ener 2. 94 101 s m 2. 076 vs s vw w 1.198 300 m m vs s cellent throwing power. Although the electrodeposits ob- The designation of the intensity of the lines is as foltained from commercial baths are fairly attractive, the lows: deposits are not as clear and bright as required for most decorative applications. Only those deposits plated over Y Strong a bright undercoat in thicknesses less than 6 microns apg pear bright. Essentially here the deposit is transparent. mmedlllm In thicknesses greater than 6 microns, there is a slight til-Weak white clouding-over of the deposit resulting in a hazy Y Weak deposit, which increases with increased thickness. It is desirable to have a clear, lustrous deposit and even more The data for the dePOslt lhcohlmh A 15 p desirable to have a clear, bright deposit. We have now 40 ducedfrom Jr Electrodeposlters Tech- 500-, 27, discovered a process utilizing special baths from which (1950 51): a$ 13 the "f 1 Values- The data 111 we are able to electrodeposit bright tinmickeL Column B is for a deposit obtained from Bath No. 2 of It is an object of this invention to provide lustrous tin- Table H harem, 15mg the pomssluhr1 of perfiuometinylr nickel alloy electrodeposits cyclohexane sulfonate as an anti-pitting agent. The bright It is also an Object of this invention to provide bright deposits recorded in Column C and Column D were from tin-nickel electrodeposits in thicknesses greater than 6 5 the Same h F that of Column B; the bath of Column microns C also containing 0.2 g./l. of phenylpropiolic acid as a The invention also contemplates improved baths elecbrighteheri and 'f of Column D containing 0f trodepositing lustrous, clear and bright tin-nickel alloys in stsammldopropyldmethyl (ghydroxyethyi)ammqmum thicknesses greater than 6 microns. dihydrogen phosphate as a brightenen The deposits of The invention further contemplates a process for elee- Columns h D Were 0015 -fh trodepositing lustrous, clear, and bright tin-nickel elec- Bhsnylprorwhc acid Phenylpmplohc flmlde, and trodeposits in thicknesses greater than 6 microns aminotriphenyl methane are useful brighteners when We discovemd that lustrous and bright timm'ckel 1 added to the baths 1n amounts between 0.01 g./1. and 0.3 trodeposits may be obtained from acidic baths which cong./l.; preferably baths containing 0.05 g./l. and 0.2 g./l. tain an eifective amount of a brightener. We discovered 55 are USFCL Y PYf 15 a 1156- that specific compounds and combinations of specific ful hnghteher when added to the bath 1h amouhth h compounds are effective brighteners for tin-nickel alloy tween and 1 Preferably a contalnlng electrodaposifion 0.2 g./l. and 0.5 g./l. are used. Stearamidopropyldi- The electrodeposit may be made on dull basis metals, m l (B hydroryethybammomum dihydrogen P although this is not preferred. As deposited initially, the Phate 1S a useful bflghtenel" when added to the bath in tin-nickel is fairly bright and as electrodeposition conamounts between 0-001 g1 and preferably tinues, the deposit becomes increasingly bright resulting baths containlng and are usedin a lustrous deposit. Tin-nickel as electrodeposited from diphenylcarbohydfazide is a useful blightenef When added standard baths may be described as cloudy-bright. The to the bath in amounts between 0.05 g./l. and 0.5 g./l.; deposit has a slight white clouded appearance. It is not preferably baths containing 0.2 g./l. and 0.3 g./l. are used.

When one of the aforementioned brighteners is used as the sole brightener in the bath, effective brightening action is not achieved when the bath contains less than the minimum concentration specified for each brightener. Smaller concentrations may be extremely effective when more than one brightener is used in combination. The maximum preferred concentration specified for each brightener is that concentration at which acceptable brightness will be achieved with the variation of conditions to be found in commercial practice. Above the preferred maximum concentration specified, the. deposit tends to become brittle at high current densities (above about 7.5 amp/sq. dm.). Above the maximum concentration specified, the brittleness becomes severe enough to cause cracking and some exfoliation so that the current density range is substantially reduced. 7

' Phosphoric acid and its salts have also been discovered to be brighteners. Phosphoric acid when added to the bath in amounts between 0.1 g./l. and 15 g./l., and preferably between 0.5 g./l. and 7 g./l., results in lustrous, hazy-bright deposits. The brightness activity is most significant in the 0.5-7.0 g./l. range. Although amounts in excess of 7.0 g./l. up to 15 g./l. do not appear to produce an increase in the brightness of the deposit, this presence does not give detrimental efiects. Above about 15 g./l., the deposit possesses a grainy appearance. Concentrations of less than 0.5 g./l. are effective when used in combination with a sufiicient concentration of another brightener. Phosphoric acid as used herein includes the ortho, pyro, metaand hypo-phosphoric acid as Well as the equivalent series of salts. The potassium, sodium, and ammonium salts are preferred.

Combinations of the various brighteners give unusually good deposits; in particular, deposits approaching mirrorbrightness have been obtained by using phosphoric acid in combination with one of the other brighteners. Although the ranges in which the individual brighteners are etiective are also the same general ranges in which they are efiective in combination, it is possible to use amounts smaller than the minimum specified concentration of one brightener, in combination with another brightener in relatively higher concentrations. The combinations of brighteners are particularly preferred in that the brightest deposits are obtained with combinations of brighteners. The use of phosphoric acid in combination with one of the other brighteners has been particularly useful in that it tends to broaden the'limits of the range of concentrations of brightener permitted in the bath. A preferred method of incorporating the brightener in the bath is to add a water solution containing 5 g./1. to 200 g./l. of phosphoric acid and 5 g./l. to 50 g./l. of at least one of the other brighteners specified herein.

Tin-nickel is deposited from acid baths, primarily from chloride and/ or fluoride baths. The preferred baths contain both chloride and fluoride anions, stannous tin in the amounts of 26 g./l. to 37.5 g./l.; and nickel in amounts between 60 g./l. and 82.5 g./l. The total fluorine for new baths is between 34 g./l. and 45 g./l. in the mixed baths. The stannic tin concentration increases in baths which are in operation. As this occurs, the fluorine should be increased so that it at least equals the total tin in the bath. The chloride content is not critical. The pH is maintained between 2 and 3.5, generally by the addition of ammonium hydroxide or hydrofluoric acid. To prevent pitting, the baths should also contain a suitable agent. A class of agents which has been found to be satisfactory includes a sulfonated cyclic fluorocarbon such as perfluoro- 4-methyl cyclohexyl sulfonic acid; perfluorocyclohexyl sulfonic acid; perfluoro-Z-methyl cyclohexyl sulfonic acid; perfiuoro-l-methyl cyclohexyl sulfonic acid; pertiuoro- 2,5-dimethyl cyclohexyl sulfonic acid; perfiuoro-4-ethyl cyclohexyl sulfonic acid; perfiuorol-isopropyl cyclohexyl sulfonic acid; and the salts of these acids. The bath is operated at high temperatures, preferably between 65 and 71 C; Typical bath formulations follow:

Nickel chloride, NiCl -6H O 300 (Nickel metal) 75 10 Sodium fluoride, NaF 28 (Fluoride) a- 13 Ammonium birluoride, N HF 35 (Fluorine) 24 Total fluorine in bath n 37 15 pH (colorimetric), 2.5

Temperature, 65 C.

Cathode current density, 3 amp/sq. dm.

Bath 2: Grams per liter Stannous chloride 49 Nickel chloride (NiCl -6H O) 300 Ammonium bifiuoride (NH HF -a 56 Ammonium hydroxide, as needed to adjust pH to 2.0-2.5 Temperature, 68 C.

All-chloride baths are generally operated at lower pHs, i.e., not greater than about 1, by the addition of hydrochloric acid. In these all-chloride baths, the tin is added in the form of stannous chloride, and the nickel in the form of nicket chloride. All of the baths are initially made up by adding the noted chemicals to water. However, equivalent chemicals may be added, e.g., stannous tin may be added in the form of the oxide or the fluoride, as well as the chloride. During operation, the tin and nickel may be replaced either chemically or by snodic corrosion of metallic anodes or a combination of both.

For the purpose of giving those skilled in the art a better understanding of the invention, the following illus trative examples are given. In the examples, tin-nickel (approximately 65% tin and nickel) was electro deposited at the conditions noted. The physical appear= ance of the deposit obtained in each example is described As noted they are lustrous and bright and in some cases they are a clear-bright.

All the samples were plated from the standard bath identified as Bath 2 of Table II hereinbefore. Plating tests were made under two different sets of conditions as specif= ically noted in each example. Most of the test cathodes were plated in a Hull Cell which is described on pages Triaminotriphenyl methane was added to the standard bath in the amount of 0.25 g./l. Under the standard plating conditions, a small copper plated zinc die cast handle was plated at an average current density of approximately 2.3 amperes per square decimeter (amp/sq. dm.) for 25 minutes to an average thickness of approximately 20 microns. The deposit was clear-bright over the decorative area of the handle to give a lustrous, attractive 70 article.

Example 2 Triaminotriphenyl methane in the amount of 0.05 g./l. was added to the standard bath which was placed in a 5 Hull Cell. In this plating cell, a smooth brass panel was 645-648 of The Metal Finishing Guidebook, 27th Edition,

Example 3 Phenylpropiolic acid in the amount of 0.2 g./l. was added to the standard bath in a small plating tank. Tinnickel was plated directly on a steel cathode at an average current density of 2.3 amp/sq. dm. for 45 minutes to give an average thickness of approximately 40 microns. At this thickness a hazy-bright deposit was obtained over the surface of the cathode.

Example 4 Phenylpropiolic acid in the amount of 0.14 g./l. was added to the standard bath formulation and placed in a Hull Cell. A smooth brass panel was plated in this cell at an average current density of 2.7 amp/sq. dm. for minutes. Over the current density range of 0.05 to 8 amp/sq. dm. the deposit was clear-bright and lustrous.

Example 5 Phenylpropiolic acid in the amount of 0.04 g./l. was added to the standard bath formulation in a Hull Cell. With a smooth brass panel as cathode plated at 2.7 amp./ sq. dm. for 10 minutes, the deposit was hazy-bright.

Example 6 Phenylpropiolic amide in the amount of 0.25 g./l. was added to the standard tin-nickel bath in a Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp./ sq. dm. for ten minutes. At the end of this time the plate was clear-bright and lustrous over all but the high current density edge of the current density range.

Example 7 Phenylpropiolic amide in the amount of 0.2 g./l. was added to the standard tin-nickel bath in a small laboratory tank. A copper-plated zinc die cast handle was plated at approximately 2.3 amp./ sq. dm. for 30 minutes. An average tin-nickel thickness of approximately 23 microns was obtained. The deposit was clear-bright and lustrous.

Example 8 Phenylpropiolic amide in the amount of 0.1 g./l. was added to the standard tin-nickel bath formulation in 21 Hull Cell. A smooth brass panel was plated for 10 minutes at an average current density of 2.7 amp/sq. dm., the deposit obtained was clear-bright over the entire current density range.

Example 9 The compound l-(p-aminophenyl)-3-methylpyrazole in the amount of 0.5 g./l. was added to the standard tinnickel formulation in 21 Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. dm. for 10 minutes. The tin-nickel deposit was clearbright over the entire panel.

Example 10 The compound l-(p-arninophenyl)-3-methylpyrazole in the amount of 0.1 g./l. was added to the standard tinnickel formulation in at Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp./ sq. dm. for 10 minutes. The tin-nickel deposit was clearbright over the entire panel.

Example 11 The compound, stearamidopropyldimethyl-(B-hydroxyethyl)-ammonium dihydrogen phosphate in the amount of 0.12 g./l. was added to the standard tin-nickel formulation in a Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. dm. for 10 minutes. The tin-nickel deposit was clear-bright over the entire panel.

Example 12 The compound, stearamidopropyldimethyl-(fl-hydroxyethyl) ammonium dihydrogen phosphate, in the amount of 0.04 g./l. was added to the standard tin-nickel formulation in a Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. dm. for 10 minutes. The tin-nickel deposit was clear-bright over the entire panel.

Example 13 The compound 1,S-diphenyldarbohydrazide in the amount of 0.4 g./l. was added to the standard tin-nickel formulation in a Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. dm.. for 10 minutes. The tin-nickel deposit was hazy-bright over the entire panel.

Example 14 The compound 1,5-diphenylcarbohydrazide in the amount of 0.10 g./l. was added to the standard tin-nickel formulation in a Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. d-m. for 10 minutes. The tin-nickel deposit was hazy-bright over the entire panel.

Example 15 The compound, phosphoric acid (H PO in the amount of 11 g./l. was added to the standard tin-nickel formulation in 2. Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. dm. for 10 minutes. The tin-nickel deposit was clear-bright over the area of the panel .below about 3 amp/sq. dm. and hazy-bright on areas above about 3 amp/sq. dm.

Example 16 The compound, phosphoric acid (H PO in the amount of 6 'g./l. was added to the standard tin-nickel formulation in a Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. dm. for 10 minutes. The tin-nickel deposit was hazy-bright over the entire panel.

Example 17 The compound, phosphoric acid (H PO in the amount of 0.6 g./l. was added to the standard tin-nickel formulation in a Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. dm. for 10 minutes. The tin-nickel deposit was hazy-bright over the entire panel.

Example 18 A combination of phenylpropiolic acid, 0.08 g./l., and stearamidopropyldimethyl fl-hydroxyethyDammonium hydrogen phosphate, 0.003 g./1., was added to the standard tin-nickel formulation in a Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. dm. for 10 minutes. The tin-nickel deposit was clear-bright over the entire panel.

Example 19 A combination of stearamidopropyldimethyl-(fi-hydroxyethyl)ammonium dihydrogen phosphate, 0.12 g./l. and phosphoric acid, 1.8 g./1. was added to the standard tin-nickel formulation in at Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. dm. for 10 minutes. The tin-nickel deposit was clear-bright over the entire panel.

Example 20 A combination of phenylpropiolic acid, 0.04 g./l. and phosphoric acid, 0.6 -g./l., was added to the standard tin-nickel formulation in a Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp./sq. dm. for 10 minutes. The tin-nickel deposit was clear-bright over the entire panel.

Example 21 A combination of phenylpropiolic amide, 0.06 g./l. and phosphoric acid, 1 g./l., was added to the standard tinnickel formulation in a Hull Cell. A smooth :brass panel was plated at an average current density of 2.7 amp./ sq. dm. for 10 minutes. The tin-nickel deposit was clearbright over the entire panel.

Example 22 A combination of triaminotriphenyl methane, 0.02 g./l., and phosphoric acid, 0.5 g./l., was added to the standard tin-nickel formulation in a Hull Cell. A smooth brass panel was plated at an average current density of 2.7 amp/sq. dm. for 10 minutes. The tin-nickel deposit was clear-bright over the entire panel.

Example 23 Example 24 A combination of l,5-diphenylcanbohydrazide, 0.1 g./l., and phosphoric acid, 2.0 g./l. was added to the standard tin-nickel formulation in a Hull Cell. A smooth brass panel was plated at an average current den'sityof 2.7 amp/sq. dm. for 10 minutes. The tin-nickel deposit was hazy-bright over the entire panel.

Similar lustrous and bright deposits are obtained using the noted additives with other acid baths, such as Bath 1 of Table II and the all-chloride bath formulation, at pH values below 1. The tin-nickel electrodeposits obtained from the bright baths were strongly oriented in the 300 plane. Utilizing these bright baths, it is possible to electrodeposit bright tin-nickel directly on most basis metals including steel, copper and copper alloys, tin, nickel and nickel alloys, etc. Conventional cleaning of the basis metal prior to electrodeposition should be practiced. The use of a bronze or copper undercoat on some basis metals, particularly those electrochemically active in acid baths, is preferred.

As many embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention includes all such modifications and variations as come within the scope of the appended claim.

We claim:

A composite metal article comprising a basis metal having a surface deposit of a lustrous bright tin-nickel alloy with layering strongly oriented in the 300 plane.

References Cited by the Examiner UNITED STATES PATENTS 2,654,703 10/1953 Brown 204-43 2,748,086 5/1956 Faust 204-43 2,926,124 2/1960- Taylor 204 43 HYLAND BIZOT, Primary Examiner. 

